Don't display show_option_none in wp_dropdown_categories when categories exist

[nofearinc]

I can't find an application of having an extra entry for show_option_none select option if we have category listing. Is there any reason to keep it there, like for external filters? If so, that still conflicts with the second example below.

First off, it is invalid since there are some categories available. Second, having both show_option_none and show_option_all displays both entries.

Related to #21856 trying to list only visible terms.

[nofearinc]

remove the conditional statement where categories do exist

[c3mdigital]

Replying to nofearinc

can't find an application of having an extra entry for show_option_none select option if we have category listing. Is there any reason to keep it >here, like for external filters? If so, that still conflicts with the second example below.

Use case: Adding multiple dropdown select filters for custom taxonomies on edit.php. I want to be able to exclude certain taxonomies from the query when filtering. The initial design takes into account that you might want to display both hence the different option values, -1 for none and 0 for all.